15 September 1835
Darwin's experience in the Galapagos would be the principle inspiration for his work, On The Origin of Species, one of those rare scientific works that fundamentally changed the people think about the world in which they live.On a mission to survey the South American coast, the Beagle reached San Cristobal (Chatham) in September 1835. The Beagle spent 5 weeks in the Galapagos carefully charting the archipelago.In the meantime, Darwin, the ship's naturalist, made careful observations about both the geology and biology of the islands. Darwin was particularly struck by the "differences between the inhabitants of the different islands" In time he came to believe that the only way to account for the great species variation was if animals were all once of the same population, but changed slowly over the eons as individual they became isolated from one another.Darwin is often credited with the theory of evolution. This is not correct, as he would freely admit. Other naturalists had developed this idea by the end of the eighteenth century. Darwin's great contribution to science was in explaining how and why evolution occurred. The answer, which he called natural selection, argues that those individuals born with characteristics making them best suited for their environment are the ones most likely to survive, and thus most likely to produce offspring.Knowing the controversy the work would surely generate, Darwin was cautious about publishing. After 20 years of carefully researching and developing sufficient evidence, On the Origin of Species was finally released in November 1859. While Darwin's theories were soon accepted by most scientists, the backlash from various faith communities has never completely subsided. Even today the teaching of evolution is tightly controlled or outright banned in some schools around the world.